Straight forward VOIP shaping problem

I have a Trixbox VOIP PBX behind a pfSense v1.2.2. I'm having what I believe to be traffic shaping problems.

Overview: We have a T-1, which tests to be about 1300/1300 kbps.

Symptoms: When I download a large file and max our download speed, VOIP will garble. This is even with the traffic shaper turned on and setup via the wizard. Whats even more strange is that ping latency to the INTERNAL interface of the pfSense from an internal machine jumps significantly when are large download is running.

Can anyone explain this behavior or how it can be resolved? I need the VOIP calls to remain smooth for their duration, no matter what load users attempt to put on the WAN connection. Thanks.

I had a similar issue with a single VPN phone, while running bittorrent.

I think I have resolved it by adding a rule that captures all non-VPN Phone traffic to a queue other than the voip queues. in the screen shot below, 192.168.1.6 is the internal address of the phone. I also set the queue that all the other traffic would go to at 75% of the overall bandwidth. This is seeming to do the trick.

My problem may not be traffic related, but possibly a hardware incompatibility.

When I go to the webui and bring up the traffic shaper, my pings to the internal interface of the pfSense increase in latency. You can see the period before I click on the traffic shaper, 1ms. Then while the rules are all loading the latency increases substantially. Then when the rules are done loading, the latency drops back to normal.